Uploaded June 2026 | Updated September 2026, 3 weeks ago
Bifrost: Alibaba's Next-Generation VPC Network with High-Performance Multipath Reliable Transport
Zihao Fan, Shanghai Jiao Tong University and Alibaba Cloud; Xing Li, Zhejiang University and Alibaba Cloud; Ye Yang, Alibaba Cloud; Bo Jiang, Shanghai Jiao Tong University; Bowen Yang, Yilong Lv, Yuke Hong, Yinian Zhou, Junnan Cai, Jiayue Xu, Yunrui Hu, Zhao Gao, Ke Sun, Yimin Liu, Xiangdong Zhang, Enge Song, Jianyuan Lu, Xiaoqing Sun, Shize Zhang, Haonan Li, Mingxin Li, Changgang Zheng, Yang Song, Jun Liang, and Biao Lyu, Alibaba Cloud; Rong Wen, Fudan University and Alibaba Cloud; Zhigang Zong and Shunmin Zhu, Alibaba Cloud
Virtual Private Cloud (VPC) has become an increasingly important infrastructure-level service that provides isolated virtual networking environments for cloud tenants. In Alibaba Cloud, over 80% of tenant applications require reliable data transport, which is currently implemented in VPC networks through guest-side TCP. However, TCP often suffers significant performance degradation when facing network instabilities in production clouds, especially for tail-latency sensitive applications such as Redis and Nginx. In this paper, we present Bifrost, the next-generation VPC network in Alibaba Cloud that provides high-performance multipath reliable transport. Bifrost employs RTT-aware multipath packet spraying to bypass failures and mitigate elephant flows, ensures in-order delivery via in-place guest reordering, achieves end-to-end reliability with delayed bitmap ACKs, and performs efficient reliability state management to support large-scale deployment. Extensive evaluation shows that Bifrost reduces tail latency by up to 307× for Redis and 66× for Nginx, achieves millisecond-level failure recovery, and supports O(100k) concurrent connections per SmartNIC.
View the full NSDI '26 program at usenix.org/conference/nsdi26/technical-sessions
Bifrost: Alibaba's Next-Generation VPC Network with High-Performance Multipath Reliable Transport
Zihao Fan, Shanghai Jiao Tong University and Alibaba Cloud; Xing Li, Zhejiang University and Alibaba Cloud; Ye Yang, Alibaba Cloud; Bo Jiang, Shanghai Jiao Tong University; Bowen Yang, Yilong Lv, Yuke Hong, Yinian Zhou, Junnan Cai, Jiayue Xu, Yunrui Hu, Zhao Gao, Ke Sun, Yimin Liu, Xiangdong Zhang, Enge Song, Jianyuan Lu, Xiaoqing Sun, Shize Zhang, Haonan Li, Mingxin Li, Changgang Zheng, Yang Song, Jun Liang, and Biao Lyu, Alibaba Cloud; Rong Wen, Fudan University and Alibaba Cloud; Zhigang Zong and Shunmin Zhu, Alibaba Cloud
Virtual Private Cloud (VPC) has become an increasingly important infrastructure-level service that provides isolated virtual networking environments for cloud tenants. In Alibaba Cloud, over 80% of tenant applications require reliable data transport, which is currently implemented in VPC networks through guest-side TCP. However, TCP often suffers significant performance degradation when facing network instabilities in production clouds, especially for tail-latency sensitive applications such as Redis and Nginx. In this paper, we present Bifrost, the next-generation VPC network in Alibaba Cloud that provides high-performance multipath reliable transport. Bifrost employs RTT-aware multipath packet spraying to bypass failures and mitigate elephant flows, ensures in-order delivery via in-place guest reordering, achieves end-to-end reliability with delayed bitmap ACKs, and performs efficient reliability state management to support large-scale deployment. Extensive evaluation shows that Bifrost reduces tail latency by up to 307× for Redis and 66× for Nginx, achieves millisecond-level failure recovery, and supports O(100k) concurrent connections per SmartNIC.
View the full NSDI '26 program at usenix.org/conference/nsdi26/technical-sessions
